Propellant compositions with metal nanoparticles

ABSTRACT

A propellant composition comprises a propellant solvent, a propellant base, and a plurality of metal nanoparticles. A powder or dried propellant composition is formed by removing at least a portion of the propellant solvent. The metal nanoparticles of the plurality of metal nanoparticles are nonionic. The plurality of metal nanoparticles functions to reduce visible light output by the propellant composition during deflagration.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/164,764, filed Mar. 23, 2021, and entitled “PROPELLANT COMPOSITIONS WITH METAL NANOPARTICLES”, the entirety of which is incorporated herein by this reference.

BACKGROUND

Propellant compositions are widely used for a variety of purposes, such as to create movement of a fluid or to generate propulsion of a vehicle, projectile, or other object. Propellant compositions are commonly used in firearm ammunition to generate propulsion of bullets and other projectiles. For example, many firearms include components that mechanically or electrically interact with a primer to ignite a propellant composition, and deflagration of the propellant composition causes propulsion of a bullet or other projectile.

Conventional propellant compositions are associated with a number of shortcomings. For example, conventional propellant compositions often burn in an inconsistent or uneven manner, which can cause projectiles or other objects propelled thereby to travel in an inconsistent or unexpected manner. Furthermore, many conventional propellant compositions output a significant amount of visible light during deflagration, often referred to as a “flash.”

The flash associated with conventional propellant compositions often gives rise to a number of problems. For example, when a user fires a firearm, a flash may indicate the position or location of the user to others, which may be undesirable for a variety of reasons. Furthermore, a flash resulting from the firing of a firearm can cause overstimulation of the retina of the user or others in proximity of the firearm.

Accordingly, there exists a need for improved propellant compositions that can facilitate a controlled, even burn during deflagration and/or facilitate a reduction in visible light output during deflagration (e.g., a reduction in flash).

BRIEF SUMMARY

Disclosed are propellant compositions containing metal nanoparticles. In one aspect, a propellant composition comprises a propellant solvent, a propellant base, and a plurality of metal nanoparticles. The metal nanoparticles are configured to reduce visible light output by the propellant composition during deflagration.

The metal nanoparticles may comprise spherical-shaped metal nanoparticles and/or coral-shaped metal nanoparticles. The metal nanoparticles may comprise one or metals such as silver, gold, cobalt, platinum, antimony, or combinations thereof. In preferred embodiments, spherical-shaped metal nanoparticles are nonionic and formed by laser ablation so that at least 99% of the metal nanoparticles have a diameter within 30% of a mean diameter and/or within ±3 nm of the mean diameter. In preferred embodiments, coral-shaped metal nanoparticles are nonionic and formed by laser ablation so that at least 99% of the metal nanoparticles have a length within 30% of a mean length and/or within ±3 nm of the mean length.

The concentration of metal nanoparticles within the propellant composition may be within a range of about 200 ppb to about 10 ppm by weight of the composition. In at least some instances, the metal nanoparticles function to modify the range of wavelengths of visible light output by the propellant composition during deflagration. The disclosed metal nanoparticles can also promote more even burn rate during deflagration.

In another aspect, an ammunition cartridge comprises a casing that includes a sidewall defining an opening and a projectile that resides within the opening. The sidewall and the projectile define an interior cavity. The ammunition cartridge also includes a propellant composition residing within the interior cavity. The propellant composition may comprise a propellant solvent, a propellant base, and a plurality of metal nanoparticles. The metal nanoparticles are configured to reduce visible light output by the propellant composition during deflagration and/or to modulate the range of wavelengths of visible light output by the propellant composition during deflagration.

The ammunition cartridge may also include a priming composition arranged proximate to the propellant composition. The priming composition is configured to ignite the propellant composition in response to a triggering condition (e.g., by actuation of a hammer or striker of a firearm). The priming composition includes a second plurality of metal nanoparticles. The second metal nanoparticles of the second plurality of metal nanoparticles may be nonionic and formed by laser ablation so that at least 99% of the second metal nanoparticles have a second diameter or length within 30% of a second mean diameter or length and/or within ±3 nm of the second mean diameter or length. The second plurality of metal nanoparticles function to reduce visible light output by the priming composition during ignition and/or to modulate the range of wavelengths of visible light output by the propellant composition during deflagration. The second plurality of metal nanoparticles of the priming composition may correspond in size, material, and/or concentration to the metal nanoparticles of the propellant composition, though in other embodiments the first and second pluralities of nanoparticles may differ in or more of such parameters.

In another aspect, a method for deflagrating a propellant composition in a manner that reduces visible light output by the propellant composition during deflagration includes providing a propellant composition and causing a triggering condition that ignites the propellant composition and causes deflagration thereof. The propellant composition includes a propellant solvent, a propellant base, and a plurality of metal nanoparticles. The metal nanoparticles of the plurality of metal nanoparticles are nonionic, and the plurality of metal nanoparticles function to reduce visible light output by the propellant composition during deflagration. The metal nanoparticles may also contribute to burn rate of the propellant composition, such by accelerating burn rate and or promoting a more uniform burn rate throughout the composition when ignited.

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an indication of the scope of the claimed subject matter.

Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the disclosure. These and other features of the present disclosure will become more fully apparent from the following description and appended claims or may be learned by the practice of the disclosure as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the above recited and other advantages and features of the disclosure can be obtained, a more particular description of the disclosure briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the disclosure and are not therefore to be considered to be limiting of its scope.

The disclosure will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 illustrates example components for forming an improved propellant composition;

FIGS. 2 and 3 illustrate the example components of FIG. 1 being combined and mixed to form the improved propellant composition;

FIG. 4A illustrates an example improved propellant composition in powder form;

FIG. 4B illustrates an example improved propellant composition in concentrated liquid form;

FIG. 5 illustrates an example ammunition cartridge that includes an improved propellant composition in powdered form;

FIG. 6 illustrates an example of visible light output when firing an ammunition cartridge that includes a conventional or standard propellant composition in powdered form;

FIGS. 7A and 7B illustrate graphical representations of data associated with visible light output when firing an ammunition cartridge that includes a conventional or standard propellant composition in powdered form;

FIG. 8 illustrates an example of visible light output when firing an ammunition cartridge that includes an improved propellant composition in powdered form;

FIGS. 9A and 9B illustrate graphical representations of data associated with visible light output when firing an ammunition cartridge that includes an improved propellant composition in powdered form; and

FIG. 10 illustrates an example flow diagram depicting acts associated with deflagrating a propellant composition in a manner that reduces visible light output by the propellant composition during deflagration.

DETAILED DESCRIPTION Overview of Propellant Compositions

Before describing various embodiments of the present disclosure in detail, it is to be understood that the disclosure is not limited to the parameters of the particularly exemplified systems, methods, apparatus, products, processes, and/or kits, which may, of course, vary. Thus, while certain embodiments of the present disclosure will be described in detail, with reference to specific configurations, parameters, components, elements, etc., the descriptions are illustrative and are not to be construed as limiting the scope of the claimed invention. In addition, any headings used herein are for organizational purposes only, and the terminology used herein is for the purpose of describing the embodiments. Neither are not meant to be used to limit the scope of the description or the claims.

In some embodiments, a propellant composition comprises a propellant solvent, a propellant base, and a plurality of metal nanoparticles. The metal nanoparticles of the plurality of metal nanoparticles are preferably nonionic, preferably formed by laser ablation, and are preferably spherical-shaped metal nanoparticles and/or coral-shaped metal nanoparticles. In preferred embodiments, spherical-shaped metal nanoparticles are formed so that at least 99% of the nanoparticles have a diameter within 30% of a mean diameter and/or within ±3 nm of the mean diameter. In preferred embodiments, coral-shaped metal nanoparticles are formed so that at least 99% of the nanoparticles have a length within 30% of a mean length and/or within ±3 nm of the mean length. The metal nanoparticles are configured to reduce visible light output by the propellant composition during deflagration and/or to modulate the range of wavelengths of visible light output by the propellant composition during deflagration. The disclosed metal nanoparticles can also promote more even burn rate during deflagration.

Those skilled in the art will appreciate, in view of the present disclosure, that at least some of the disclosed embodiments may facilitate improvements over conventional propellant compositions. For example, improved propellant compositions of the present disclosure include metal nanoparticles that can beneficially provide a controlled, even burn during deflagration, thereby facilitating consistent and/or reliable performance of devices (e.g., firearms) that implement the improved propellant compositions.

Furthermore, the improved propellant compositions of the present disclosure can facilitate a reduction in visible light output during deflagration, which is a surprising and unexpected result. A reduction in visible light output during deflagration may assist in concealing the location of use of a device that utilizes an improved propellant composition (e.g., a firearm). In addition, the reduction in visible light output during deflagration provided by the propellant compositions of the present disclosure may prevent overstimulation of a user's or bystander's retina during deflagration, which may prevent disorientation or inability to see clearly while operating a device that implements an improved propellant composition.

Still furthermore, the improved propellant compositions of the present disclosure may facilitate a change in wavelength of visible light output during deflagration, which is yet another surprising and unexpected result. For instance, an improved propellant composition may facilitate an elongation of the wavelengths of visible light output during deflagration. As an example, during low light activities (e.g., nighttime activities), when the rods of the human eye are more active to facilitate vision relative to the cones of the human eye, the elongated wavelengths may prevent or limit the rods of the human eye from becoming oversaturated and may therefore help to prevent disturbance of user vision during low light activities.

Having described some of the various high-level features and benefits of the disclosed embodiments, attention will now be directed to FIGS. 1-10 These Figures illustrate various conceptual representations, architectures, methods, and/or supporting illustrations related to the disclosed embodiments.

FIG. 1 illustrates example representation of components for forming an improved propellant composition. In particular, FIG. 1 illustrates a propellant base 102 and a propellant solvent 104 that includes metal nanoparticles 106 dispersed therein. The propellant base 102 of FIG. 1 advantageously comprises nitrocellulose, although any suitable base for forming propellant compositions may be used, such as, by way of non-limiting example, nitroglycerine, nitroguanidine, and/or others. Similarly, the propellant solvent 104 may comprise any suitable solvent for dissolving a propellant base to form a propellant composition, such as acetone and/or others known in the art. The metal nanoparticles 106 shown in FIG. 1 are colloidally suspended within the propellant solvent 104 (e.g., acetone).

FIG. 2 illustrates the propellant solvent 104 with the metal nanoparticles 106 included therein being combined with the propellant base 102 in a mixing reservoir 202, as indicated in FIG. 2 by the dashed arrows extending from the propellant base 102 and the propellant solvent 104/metal nanoparticles 106 toward the mixing reservoir 202.

FIG. 3 illustrates the components being mixed together in the mixing reservoir 202 to allow the propellant base 102 to dissolve into the propellant solvent 104 to form a liquid propellant solution 302. In this way, the metal nanoparticles 106 can be incorporated into the liquid propellant solution 302 at the nitrocellulose level and disbursed throughout the liquid propellant solution 302.

As illustrated in FIG. 4A, the liquid propellant solution 302 may be formed into a powder composition 402, such as by removing the liquid by evaporation. The powder composition 402 may be utilized as a propellant for various purposes, such as to propel projectiles in a firearm context.

In some embodiments, the liquid propellant solution 302 (or the powder 402 derived therefrom) can be combined with one or more additional propellant bases (e.g., an additional nitrocellulose-based, nitroglycerine-based, and/or nitroguanidine-based composition) to form a multi-base propellant composition (e.g., double-based composition). For example, FIG. 4B illustrates the liquid propellant solution 302 being separated into composition concentrates 404, which may be combined with one or more other propellant bases (which may themselves omit metal nanoparticles) to form double-base propellants that include a desired total concentration of metal nanoparticles.

The metal nanoparticles 106 used to form a liquid propellant solution 302 (and/or products thereof, such as the powder composition 402, other dry or partially dried propellant composition, and/or concentrates 404) for forming a propellant composition (whether double-base or not) may be configured to provide various effects during deflagration of propellant compositions that incorporate the metal nanoparticles 106. Effects provided by the metal nanoparticles 106 may include, by way of non-limiting example, facilitating controlled burn and/or modifying attributes of visible light output during deflagration (e.g., illuminance, intensity, and/o wavelength).

The material, size, size distribution, and/or shape of the metal nanoparticles 106 may affect the properties of the metal nanoparticles 106, which may cause propellant compositions that include the metal nanoparticles 106 to exhibit one or more of the foregoing effects. Furthermore, the concentration of the metal nanoparticles 106 within a propellant composition may determine the magnitude of the effects exhibited by the propellant composition during deflagration.

Additional Nanoparticle Features

In some embodiments, the metal nanoparticles may comprise nonionic, ground state metal nanoparticles. The metal nanoparticles may be formed from one or more of a variety of materials, such as, by way of non-limiting example, silver, gold, platinum, palladium, rhodium, osmium, ruthenium, rhodium, rhenium, molybdenum, copper, iron, nickel, tin, beryllium, cobalt, antimony, chromium, manganese, zirconium, tin, zinc, tungsten, titanium, vanadium, lanthanum, cerium, heterogeneous mixtures thereof, and/or alloys thereof.

The size and/or shape of metal nanoparticles may be selected to provide desired catalytic properties for facilitating any desired effects described herein, and the size/shape may depend on the material(s) of the metal nanoparticles. In some embodiments, the metal nanoparticles comprise spherical-shaped metal nanoparticles, coral-shaped metal nanoparticles, or a combination or blend of spherical-shaped metal nanoparticles and coral-shaped metal nanoparticles.

Where the metal nanoparticles comprise spherical-shaped metal nanoparticles, the spherical-shaped metal nanoparticles have a solid core. Furthermore, in some instances, the spherical-shaped metal nanoparticles may have only internal bond angles and no external edges or bond angles, making the spherical-shaped metal nanoparticles highly resistant to ionization, highly stable, and highly resistant to agglomeration.

In some embodiments, spherical-shaped metal nanoparticles have a diameter of about 40 nm or less, about 35 nm or less, about 30 nm or less, about 25 nm or less, about 20 nm or less, about 15 nm or less, about 10 nm or less, about 7.5 nm or less, or about 5 nm or less. One will appreciate, in view of the present disclosure, that the diameter of spherical-shaped metal nanoparticles may be varied for different materials in order to provide the desired properties to facilitate the desired effects during deflagration (e.g., visible light output reduction/modification, controlled burn, etc.). For example, spherical-shaped metal nanoparticles formed from gold may exhibit desired properties with a diameter of about 4 nm, whereas spherical-shaped metal nanoparticles formed from silver and/or antimony may exhibit desired catalytic properties with a somewhat larger diameter (e.g., about 10 nm).

In some embodiments, spherical-shaped nanoparticles can have a particle size distribution such that at least 99% of the nanoparticles have a diameter that is within about 30% of the mean diameter of the nanoparticles, or within about 20% of the mean diameter, or within about 10% of the mean diameter. Additionally, or alternatively, spherical-shaped metal nanoparticles can have a particle size distribution such that at least 99% of the spherical-shaped metal nanoparticles have a particle size that is within ±3 nm of the mean diameter, ±2 nm of the mean diameter, or ±1 nm of the mean diameter.

Coral-shaped metal nanoparticles, in contrast to spherical-shaped metal nanoparticles, have a non-uniform cross-section and a globular structure formed by multiple, non-linear strands joined together (e.g., without right angles). In some instances, similar to spherical-shaped nanoparticles, coral-shaped nanoparticles may have only internal bond angles and no external edges or bond angles. In this way, coral-shaped nanoparticles may be highly resistant to ionization, highly stable, and highly resistant to agglomeration.

In some embodiments, coral-shaped nanoparticles comprise a length (along a longest dimension) within a range of about 15 nm to about 100 nm, or about 25 nm to about 95 nm, or about 40 nm to about 90 nm, or about 60 nm to about 85 nm, or about 70 nm to about 80 nm. In most instances, coral-shaped nanoparticles may typically have a larger size than corresponding spherical-shaped nanoparticles. For example, testing has suggested that the benefit of coral-shaped particles is not a function of the specific size of the coral-shaped nanoparticles, leading to the conclusion that the beneficial catalytic properties exhibited by coral-shaped nanoparticles are the result of small protrusions on the coral-shaped particles that mimic the effect of small spherical-shaped nanoparticles (e.g., spherical-shaped nanoparticles with a diameter of about 4 nm).

In some embodiments, coral-shaped nanoparticles can have a particle size distribution such that at least 99% of the nanoparticles have a length (along a longest dimension) that is within about 30% of the mean length (along the longest dimension) of the nanoparticles, or within about 20% of the mean length, or within about 10% of the mean length. Additionally, or alternatively, coral-shaped metal nanoparticles can have a particle size distribution such that at least 99% of the coral-shaped metal nanoparticles can have a length that is within ±3 nm of the mean length, ±2 nm of the mean length, or ±1 nm of the mean length.

In accordance with the present disclosure, metal nanoparticles for use in a propellant base can be manufactured or formed in a variety of ways. In some instances, spherical or coral-shaped metal nanoparticles can be formed by laser ablation, which may improve the uniformity of the particle size distribution of spherical-shaped and/or coral-shaped metal nanoparticles and thereby allow the enhanced effects described herein.

Examples of spherical-shaped metal nanoparticles formed by laser ablation are described in U.S. Pat. Nos. 9,849,512 and 10,137,503 to Niedermeyer. Examples of non-spherical (e.g., coral-shaped) metal nanoparticles formed by laser ablation are described in U.S. Pat. No. 9,919,363 to Niedermeyer. For purposes of disclosure, the foregoing patents are incorporated herein by reference in their entireties.

As noted hereinabove, the concentration of metal nanoparticles within a propellant composition may determine the magnitude of the effects exhibited by the propellant composition during deflagration. In some embodiments, to provide beneficial effects such as reduced flash, modified visible light output wavelength, and/or controlled burn, an improved propellant composition can include a concentration of metal nanoparticles in a range of about 200 ppb to about 10 ppm by weight (about 0.2 mg/kg to about 10 mg/kg). It has been found that, in some instances, a propellant composition that comprises less than about 200 ppb (e.g., less than about 0.2 mg/kg) of metal nanoparticles may fail to provide noticeable effects. Furthermore, it has been found that, in some instances, a propellant composition that comprises more than about 10 ppm (e.g., more than about 10 mg/kg) of metal nanoparticles may include an excess of metal nanoparticles that may not significantly further improve and/or contribute to the exhibited effect(s) and are therefore unnecessary and potentially wasteful.

Accordingly, preferred propellant compositions disclosed herein can have a concentration of metal nanoparticles in a range of about 200 ppb to about 10 ppm by weight (about 0.2 mg/kg to about 10 mg/kg). In some embodiments, propellant compositions disclosed herein can have a concentration of metal nanoparticles in a range of about 250 ppb to about 3 ppm, more preferably in a range of about 300 ppb to about 1 ppm, even more preferably in a range of about 350 ppb to about 800 ppb, and most preferably in a range of about 400 ppb to about 600 ppb (e.g., in a range of about 0.25 mg/kg to about 3 mg/kg, about 0.3 mg/kg to about 1 mg/kg, about 0.35 mg/kg to about 0.8 mg/kg, or about 0.4 mg/kg to about 0.6 mg/kg). When a propellant composition is provided in a concentrated form (e.g., for mixing with one or more other propellant bases), the concentration of nanoparticles can be adjusted accordingly so as to provide the foregoing concentrations when mixed with the other components to form a resulting, ready-to-use product.

Ammunition Embodiments

An improved propellant composition that includes metal nanoparticles, according to the present disclosure, may be implemented by various devices and/or for various purposes. One example implementation is in ammunition cartridges.

FIG. 5 illustrates an example ammunition cartridge 500 that includes an improved propellant composition in powdered form. In particular, FIG. 5 shows the ammunition cartridge 500 as including a casing 502, which may be formed from any suitable material, such as brass, steel, other metals or alloys, and/or other materials known in the art.

The casing 502 includes a sidewall 504 that defines an opening 506 at one end of the casing 502. As is shown in FIG. 5 , a projectile 508 resides at least partially within the opening 506. The projectile 508 of FIG. 5 is illustrate as a bullet, which is configured to be propelled during shooting (e.g., as a result of deflagration of a propellant composition) and may comprise any suitable material such as one or more of copper, lead, steel, polymer, rubber, wax, and/or others known in the art.

FIG. 5 further shows that a combination of one or more surfaces of the projectile 508 (when residing at least partially within the opening 506 formed by the sidewall 504 of the casing 502, as shown) and the sidewall 504 of the casing 502 define an interior cavity 510 for containment of a propellant composition 512. FIG. 5 conceptually illustrates the propellant composition 512 being in powdered form, and the propellant composition 512 may at least partially correspond to and/or be derived from any improved propellant composition as described herein. For instance, the propellant composition 512 may comprise spherical-shaped and/or coral-shaped metal nanoparticles in a concentration in a range of about 200 ppb to about 10 ppm by weight (e.g., about 0.2 mg/kg to about 10 mg/kg) and may be formed or derived from a liquid propellant solution 302 (and/or products derived therefrom, such as powder composition 402, dry or partially dried composition, and/or composition concentrates 404) as described hereinabove with reference to FIGS. 1-4B.

FIG. 5 also illustrates the ammunition cartridge 500 as including a primer 514, which may be implemented as a cup (e.g., formed from metal) that contains a priming composition 516 disposed therein. FIG. 5 shows the primer 514 positioned within a recess in a center of the base of the casing 502. The primer 514 may be configured to ignite in response to a triggering condition, such as in response to a mechanical force (e.g., from a striker or hammer of a firearm) or electrical signal. The priming composition may comprise any suitable components to facilitate such functionality, including, but not limited to, any non-corrosive, lead-free, non-toxic, and/or non-mercuric priming compositions known in the art.

FIG. 5 further illustrates an opening 518 between the recess in the base of the casing 502 (e.g., where the primer 514 resides) and the interior cavity 510. In this regard, in response to the primer 514 becoming ignited, the propellant composition 512 disposed within the interior cavity is ignited, such that the primer 514 is configured to ignite the propellant composition 512 in response to the triggering condition.

In some embodiments, the priming composition 516 may include metal nanoparticles disbursed therethrough (in addition to or as an alternative to including nanoparticles in the propellant composition 512). Such metal nanoparticles may include any of the metal nanoparticle embodiments described herein. For example, in some instances, the metal nanoparticles of the priming composition 516 may be nonionic and/or be formed by laser ablation, may be spherical-shaped and/or coral-shaped, and may be formed such that at least 99% of the metal nanoparticles have a diameter or length that is within 30% of a mean diameter or length and/or within ±3 nm of the mean diameter or length.

As with the propellant composition 512, the metal nanoparticles of the priming composition 516 can provide desirable effects during ignition and/or deflagration of the priming composition based on beneficial combinations of material, size, size distribution, shape, and/or concentration of the metal nanoparticles. Such benefits include a reduced amount of and/or modified wavelength(s) of the visible light emitted during ignition and/or deflagration of the priming composition 516.

In some instances, for a particular ammunition cartridge 500, both the propellant composition 512 and the priming composition 516 can include respective pluralities or sets of metal nanoparticles (e.g., a first plurality or set of metal nanoparticles incorporated into the propellant composition 512 and a second plurality or set of metal nanoparticles incorporated into the priming composition). Where both the propellant composition 512 and the priming composition 516 include respective pluralities or sets of metal nanoparticles, one will appreciate, in view of the present disclosure, that the separate pluralities or sets of metal nanoparticles may correspond to one another in one or more of size, size distribution, material, concentration, and/or shape, or may be different from one another according to one or more of said parameters.

In some embodiments, a propellant composition 512 and a priming composition 516 of an ammunition cartridge may each comprise spherical-shaped metal nanoparticles made of cobalt and/or platinum, where the concentration of metal nanoparticles in both the propellant composition 512 and the priming composition 516 is in a range of about 200 ppb to about 10 ppm, or about 250 ppb to about 3 ppm, or about 300 ppb to about 1 ppm, about 350 ppb to about 800 ppb, or about 400 ppb to about 600 ppb (or alternatively any other concentration range constructed using any of the foregoing as endpoints). In another example, the propellant composition 512 may comprise spherical-shaped cobalt and/or platinum nanoparticles, whereas the priming composition 516 may comprise coral-shaped cobalt and/or platinum nanoparticles.

In yet another example, the propellant composition 512 may comprise a concentration of metal nanoparticles that is different than a concentration of metal nanoparticles within the priming composition 516. In some implementations, differences in concentrations of metal nanoparticles as between a propellant composition 512 and a priming composition 516 may facilitate desirable effects (e.g., reduction/modification in flash) during deflagration in a manner that accounts for differences in the components of the priming composition 516 and the propellant composition 512 (e.g., to provide desirable effects in a manner that avoids wasting metal nanoparticles).

In some instances, the concentration of metal nanoparticles in the propellant composition 512 is higher than the concentration of metal nanoparticles in the priming composition 516. For example, the concentration of nanoparticles within the priming composition 516 may be within a range of about 300 ppb to about 499 ppb, whereas the concentration of nanoparticles within the propellant composition 512 may be within a range of about 500 ppb to about 700 ppb. In other instances, the concentration of metal nanoparticles in the priming composition 516 is higher than the concentration of metal nanoparticles in the propellant composition 512 (e.g., within a range of about 300 ppb to about 499 ppb for the propellant composition 512 and within a range of about 500 ppb to about 700 ppb for the priming composition 516).

Although FIG. 5 and the attendant description focus, in at least some respects, on an ammunition cartridge with a centerfire construction, those skilled in the art will recognize, in view of the present disclosure, that other forms and/or configurations for ammunition cartridges may comprise a propellant composition and/or priming composition that include(s) metal nanoparticles, in accordance with the present disclosure (e.g., internal priming configurations such as pinfire, rimfire, electric-primed, or others; external priming configurations such as matchlock, wheel-lock, flintlock, cap lock, electric-fired, or others; shotgun ammunition; etcetera).

Other embodiments comprise ammunition without a casing (i.e., “caseless ammunition”). For example, caseless ammunition may include a solid mass of the propellant composition with cavities formed therein to receive the projectile and primer components. The projectile and primer may be glued in place within the corresponding cavities of the mass of propellant composition. The propellant composition of caseless ammunition embodiments may be formulated as in any of the other embodiments described herein.

Flash Effects

FIG. 6 illustrates an example of visible light output when firing an ammunition cartridge that includes a conventional or standard propellant composition in powdered form or other solid or semi-solid form, as well as a conventional or standard priming composition. As used herein, a “conventional propellant composition” or a “standard propellant composition” is a propellant composition that omits metal nanoparticles as described herein. Similarly, a “conventional priming composition” or a “standard priming composition” is a priming composition that omits metal nanoparticles as described herein.

As is evident from FIG. 6 , a significant amount of visible light is output during shooting when using a conventional propellant composition and a conventional priming composition. For example, FIG. 6 illustrates a white core 602, as well as “sparkles” 604 that extend or emit from the barrel of the firearm during shooting.

FIGS. 7A and 7B illustrate graphical representations of data associated with the visible light output from the firing of the ammunition cartridge as illustrated in FIG. 6 (i.e., for an ammunition cartridge that includes a conventional propellant composition and a conventional priming composition). In particular, FIG. 7A shows that the visible light output from firing the ammunition cartridge (as shown in FIG. 6 ) results in a peak illuminance of about 250 lux. FIG. 7B shows the illuminance of light detected for specific wavelengths, in particular 615 nm, 525 nm, and 465 nm, showing that much of the detected light is made up of shorter wavelengths (e.g., below 465 nm).

Such visible light output (e.g., as represented in FIGS. 6 through 7B) can present problems for users operating firearms and/or others within proximity to the firearm being used. For example, significant visible light output may undesirably disclose the location of use of the firearm and/or may cause disruptions to user or bystander vision, such as causing overstimulation of the retina and/or causing the saturation of the rods of the eyes.

FIG. 8 illustrates an example of visible light output when firing an ammunition cartridge that includes an improved propellant composition, such as in powdered or other solid or semi-sold form, as well as an improved priming composition (e.g., at least partially corresponding to ammunition cartridge 500, as described hereinabove with reference to FIG. 5 ). As used herein, an “improved propellant composition” is a propellant composition that includes metal nanoparticles as described herein. Similarly, an “improved priming composition” is a priming composition that includes metal nanoparticles as described herein. The propellant composition of the ammunition cartridge captured during firing in FIG. 8 comprised a concentration of metal nanoparticles of about 500 ppb or about 0.5 mg/kg.

As is evident from a comparison between FIG. 6 and FIG. 8 , the use of an improved propellant composition and an improved priming composition operates to significantly reduce the visible light output by an ammunition cartridge during shooting. For example, the white core 802 evident during shooting as represented in FIG. 8 is significantly diminished as compared to the white core 602 evident during shooting as represented in FIG. 6 . Similarly, the sparkles 804 evident during shooting as represented in FIG. 8 are significantly diminished as compared to the sparkles 604 evident during shooting as represented in FIG. 6 .

FIGS. 9A and 9B illustrate graphical representations of data associated with visible light output from the firing of the ammunition cartridge as illustrated in FIG. 8 . In particular, the top graph illustrated in FIG. 9A shows that the visible light output from firing the ammunition cartridge as shown in FIG. 8 results in a peak illuminance of about 150 lux, resulting in a significant reduction in visible light output as compared with approximately 250 lux for conventional ammunition as represented in FIG. 7A (which shows visible light output during shooting using a conventional propellant composition and a conventional priming composition).

The reduction in the illuminance in visible light output evident from a comparison between FIGS. 6-7A and FIGS. 8-9A demonstrates that the use of metal nanoparticles in propellant compositions and/or priming compositions, as described herein, may advantageously provide for flash modifications that allow users to avoid overstimulation of the retina and in a manner that at least partially assists in preventing the illumination of the environment surrounding the firearm during shooting, which are surprising and unexpected results.

Furthermore, FIG. 9B shows the illuminance of light detected for the wavelengths of 615 nm, 525 nm, and 465 nm. FIG. 9B shows that utilizing an improved propellant composition facilitates a change in the amount of output light attributable to certain wavelengths. For example, FIG. 9B shows that the amount of output light attributable to the 615 nm, 525 nm, and 465 nm wavelengths is increased by use of the improved propellant composition (compare to FIG. 7B). Such results lead to the conclusion that the use of metal nanoparticles in the propellant composition and the priming composition result in an elongation of the wavelengths of visible light output during shooting. Such an elongation, or “red-shifting”, of wavelengths may increase the red content of the visible light output during shooting. This may at least partially reduce oversaturation of the rods of user eyes during shooting in low light environments/contexts, where rods are more susceptible to saturation effects from light of shorter wavelengths. Accordingly, implementations of the present disclosure may at least partially reduce the impact of shooting on a user's natural night vision, which is another surprising and unexpected result.

Methods of Use

The following discussion now refers to a number of methods and method acts associated with deflagrating a propellant composition in a manner that reduces visible light output by the propellant composition during deflagration. FIG. 10 illustrates an example flow diagram 1000 depicting acts associated with deflagrating a propellant composition in a manner that reduces visible light output by the propellant composition during deflagration.

Act 1002 of flow diagram 1000 includes providing a propellant composition that includes metal nanoparticles. The propellant composition may correspond to any propellant composition described herein. For example, the propellant composition may comprise spherical-shaped and/or coral-shaped metal nanoparticles composed of one or more of silver, gold, platinum, palladium, rhodium, osmium, ruthenium, rhodium, rhenium, molybdenum, copper, iron, nickel, tin, beryllium, cobalt, antimony, chromium, manganese, zirconium, tin, zinc, tungsten, titanium, vanadium, lanthanum, cerium, heterogeneous mixtures thereof, and/or alloys thereof. The metal nanoparticles may be nonionic and may be formed by laser ablation so that at least 99% of the metal nanoparticles have a diameter or length within 30% of a mean diameter or length and/or within ±3 nm of the mean diameter or length.

Act 1004 of flow diagram 1000 includes causing a triggering condition that ignites the propellant composition and causes deflagration thereof. In some instances, the triggering condition includes applying a mechanical force or electrical current to a priming composition that is operable to ignite the priming composition and thereby ignite the propellant composition. For example, in some instances, the triggering condition may be facilitated by pulling a trigger mechanism of a firearm to actuate a hammer or striker of a firearm.

After igniting the propellant composition via the triggering condition, the metal nanoparticles of the propellant composition reduce visible light output by the propellant composition during deflagration. The metal nanoparticles of the propellant composition may additionally, or alternatively, modify the wavelength of the visible light output as described herein, and/or facilitate a controlled burn of the propellant composition during deflagration. Furthermore, as described hereinabove, the priming composition (where implemented) for igniting the propellant composition may include a second or additional plurality of metal nanoparticles, which may provide benefits during ignition and/or deflagration of the priming composition that are similar to those described above for deflagration of the propellant composition.

Although the present disclosure focuses, in at least some respects, on improved propellant compositions that include metal nanoparticles for implementation in ammunition cartridges, it should be noted that the improved propellant compositions of the present disclosure may be implemented in other devices and/or in other contexts, such as, by way of non-limiting example, propulsion of projectiles other than bullets, vehicle or vessel propulsion, primary explosive compounds, movement of fluids, and/or others.

One will appreciate how any feature or operation disclosed herein may be combined with any one or combination of the other features and operations disclosed herein. Additionally, the content or feature in any one of the Figures may be combined or used in connection with any content or feature used in any of the other figures. In this regard, the content disclosed in any one Figure is not mutually exclusive and instead may be combinable with the content from any of the other Figures.

The present invention may be embodied in other specific forms without departing from its spirit or characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

1. A propellant composition, comprising: a propellant solvent; a propellant base; and a plurality of metal nanoparticles, the metal nanoparticles of the plurality of metal nanoparticles being nonionic, wherein the plurality of metal nanoparticles functions to reduce visible light output by the propellant composition during deflagration.
 2. The propellant composition of claim 1, wherein the plurality of nanoparticles are formed by laser ablation.
 3. The propellant composition of claim 1, wherein the metal nanoparticles comprise one or more of silver, gold, cobalt, platinum, or antimony.
 4. The propellant composition of claim 1, wherein the metal nanoparticles comprise spherical-shaped metal nanoparticles.
 5. The propellant composition of claim 4, wherein at least 99% of the spherical-shaped metal nanoparticles have a diameter within 30% of a mean diameter and/or within ±3 nm of the mean diameter.
 6. The propellant composition of claim 5, wherein the mean diameter is about 40 nm or less.
 7. The propellant composition of claim 1, wherein the metal nanoparticles comprise coral-shaped nanoparticles.
 8. The propellant composition of claim 7, wherein at least 99% of the metal nanoparticles have a length within 30% of a mean length and/or within ±3 nm of the mean length.
 9. The propellant composition of claim 8, wherein the mean length of the coral-shaped nanoparticles is within a range of about 15 nm to about 100 nm.
 10. The propellant composition of claim 1, wherein a concentration of the metal nanoparticles within the propellant composition is within a range of about 200 ppb to about 10 ppm.
 11. The propellant composition of claim 1, wherein the metal nanoparticles modify a range of wavelengths of visible light output by the propellant composition during deflagration.
 12. The propellant composition of claim 1, wherein the propellant solvent comprises acetone.
 13. The propellant composition of claim 1, wherein the propellant base comprises one or more of nitrocellulose, nitroglycerine, or nitroguanidine.
 14. The dry or powdered propellant composition manufactured by a process comprising: providing the propellant composition of claim; and removing of at least a portion of the propellant solvent.
 15. The dry or powdered propellant composition of claim 14, wherein the dry or powdered propellant composition comprises a multi-base propellant formed using an additional second propellant base.
 16. An ammunition cartridge, comprising: a projectile; and a dry or powdered propellant composition, the propellant composition comprising: a propellant base; and a plurality of metal nanoparticles dispersed into the propellant base, the metal nanoparticles of the plurality of metal nanoparticles being nonionic, wherein the plurality of metal nanoparticles functions to reduce visible light output by the propellant composition during deflagration.
 17. The ammunition cartridge of claim 0, further comprising: a casing, wherein the projectile is coupled to the casing, the casing and the projectile defining an interior cavity, and wherein the propellant composition resides within the interior cavity; and a priming composition arranged proximate to the propellant composition, the priming composition being configured to ignite the propellant composition in response to a triggering condition.
 18. The ammunition cartridge of claim 17, the priming composition comprising a second plurality of metal nanoparticles, the metal nanoparticles of the second plurality of metal nanoparticles being nonionic and formed by laser ablation, wherein the second plurality of metal nanoparticles functions to reduce visible light output by the priming composition during ignition.
 19. The ammunition cartridge of claim 16, wherein the projectile is embedded within the propellant composition and wherein the ammunition cartridge is caseless.
 20. A method of deflagrating a propellant composition in a manner that reduces visible light output by the propellant composition during deflagration, the method comprising: providing a propellant composition comprised of: a propellant base; and a plurality of metal nanoparticles, the metal nanoparticles of the plurality of metal nanoparticles being nonionic, wherein the plurality of metal nanoparticles functions to reduce visible light output by the propellant composition during deflagration; and causing a triggering condition that ignites the propellant composition and causes deflagration thereof, the metal nanoparticles of the propellant composition reducing visible light output by the propellant composition during deflagration. 